Stencil sheet



Patented a. 26, 1926.

UNITED STATES PATENT ,OFFICE.

RICHARD RA T, or VIENNA, AUs'IrRIA, .ASSIGNOR, BY MESNE ASSIGNMENTS, ro .1). GES'IETNER, LIMITED, or LONDON, ENGLAND, A CORPORATION.

STENCIL SHEET.

No Drawing. Original application file d November 16, 1922, Serial No. 601,415, and in Austria October 11, 1922. Divided and this application filed December. 21, 1923. Serial No, 682,090.

The present application is a division of my copending application, Serial No. 60l,- .415, filed November 16, 1922, for stencilsheet.

According to my invention the ,manufacturing of a protein stencilsheet, which without being hygroscopic or including water and without preliminary moistening can be used in a perfectly dry state for preparing the stencil, is realized by adding to the coating mass esters of high molecular weight to such an amount, that in preparing the stencil 1n the typewriting machine by. the impact of the type only those parts of the coating mass are removed, which are directly struck by the protruding lines of the steeltype forming the characters, whilst the interstitial spaces bordered all around by the lines forming the characters will not be stamped out. Of the substances appropriate for such additions may by way of examples be named: fatty substances or similar esters of high molecular weight, oils and different kinds of wax. For obtaining stencil sheets eificiently operating without moistening the substances adapted for diminishing the brittleness of the ,dry coagulated protein by their own efliciency have to amount to many times 1 the weight of the protein contained in the,

so coatin mass. If the chosen substance to be ad ed is soluble in a solvent, which is also ca able of'dissolving the protein, the dissolving is done simultaneously in one operation, otherwise the substance is added to the solution of the proteinin the form of anemulsion orof a suspension or of a colloidal solution. lhe coating of the open porous base, preferably aper, is efiected either by dipping it into th 40 or else by spreading the solution onit by means of a brush or sponge, or in other known manner. 1 D

After the coating has been dried, the sheet isdrawn through a strong solution of for- 4 5 maldehyde for the purpose of coagulating the protein and then dried again. Where in the appended claims the term oleaginous is used, it is employed as denoting bodies of an oily or unctuous character. 1

What I claim is:

1. A stencil sheet comprising a base of open porous material coated with a come mixed solution position substantially free from water and hygroscopic materials, consisting essentially of a gelatinized organic colloid deposited from an aqueous medium and a fatty acid ester of high molecular weight and of an ester being present in a proportion sufficient,

to maintain the composition permanently in a state in which it may be stencilized when substantially free from moisture.

3. A stencil sheet comprising a base of open porous material coated with a composition consisting essentially of an emulsion of a gelatinized organic lcolloid deposited from an aqueous medium and an oleaginous fatty acid ester in a proportion sufficient to ,maintain the composition permanently in a state in which it may be stencilized when substantially free from moisture. I,

4. A stencil sheet comprising a base of open porousmaterial coated with a composition consisting essentially: of an emulsion of a gelatinized protein and an oleaginous fatty acid ester in a proportion sufficient to maintain the composition permanently in a state in which it may be stencilized when substantially free from moisture.

5. A stencil sheet comprising a base of open porous material coated with a composition consisting essentially of a coagulated protein and an oleaginous ester of a fatty acid, said oleaginous ester being present in a proportion sufiicient to maintain the composition permanently in a state in which it may be stencilized when substantially free from moisture.

6. A stencil sheet comprising a base of open porous material coated with a composition substantially free from water and hygroscopic material and containing a gelatinized organic colloid deposited from an aqueous medium and a proportion of an oleaginous fatty acid ester adapted to disolated in an aqueous medium and a pro-V portion of a fatty acid ester of high boiling point sufficient to maintain the composition permanently in a state in which it may be stencilized when substantially. free from moisture, and rendering the coating'composition substantially air dry. y

8. Theprocess for the manufacture of stencil sheets adapted for stencilization by pressure which comprises coating a base of open porous material with a composition consisting essentially of a protein solated in an aqueous medium "and a proportion of an oleaginous fatty acid esten material of high boiling point, sufiicient to maintain the composition permanently in a state in which it may be stencilized when substantein and tially free from moisture, and rendering (tihe coating composition substantially air 80 9. The process for "the manufacture of stencil sheets adapted for stencilization by pressure in a dry state which comprises coating a base of open porous material with an aqueous disperse system including a prolycerides of fatty acidsin a state of colloitlal dispersion, said glycerides of 1 fatty acids being present in a proportion v suilicient to maintain the composition per- 40 manently ina state in which it may be stencilized when substantially free from moisture, drying the coating and hardening the protein. i I

10. The process for the manufacture of stencil sheets adapted for stencilization by pressure in a dry state which comprises coat- Y ing a base oi open porous material with an aqueous disperse system including a gelatinizipg organic colloid and an oil in a state of colloidal dispersion, such composition being substantially free from hygroscopic substances and drying the coating.

In testimony whereof I have aflixed my signature. v a

. RICHARD LAN-T. 

